Report on Ibu (Indonesia) — September 2008

Bulletin of the Global Volcanism Network, vol. 33, no. 9 (September 2008)
Managing Editor: Richard Wunderman.

Ibu (Indonesia) Minor ash emissions during June-August 2008 and inferred dome growth

Please cite this report as:

Global Volcanism Program, 2008. Report on Ibu (Indonesia). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 33:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200809-268030.

Volcano Profile |  Complete Bulletin


Ibu

Indonesia

1.488°N, 127.63°E; summit elev. 1325 m

All times are local (unless otherwise noted)


During late March through late April 2008, the Center of Volcanology and Geological Hazard Mitigation (CVGHM) described mainly white plumes emitted from Ibu. On at least five days, however, the plumes were gray. During 17-31 March, frequent white plumes rose to an altitude of 1.5 km. On 31 March the plume altitudes increased to 1.6 km.

During 4-5 April 2008, seismicity increased in amplitude and plume altitude increased to 1.8-2.0 km. On 5 April, the eruption plume was gray and material fell around the crater. Residents of nearby communities were not permitted to climb or approach the crater.

Plumes that were possibly gray rose to altitudes between 1.6 and 1.9 km during 6-17 April. Gray plumes rose to altitudes of 2-2.1 km during 18-21 April. On 21 April, CVGHM warned that residents and tourists were not permitted within 2 km of the crater.

Steam plumes rose above the crater during late May to late August 2004 (BGVN 30:03). Thermal anomalies detected by the MODIS instruments triggered MODVOLC thermal alerts (table 1) during that interval and the last quarter of 2004; alerts were also noted during February 2005, but not in 2006 and 2007. Thermal anomalies were again measured by the MODIS instrument in mid-May 2008 and continued to be detected through late October.

Table 1. MODVOLC thermal anomalies over Ibu from late August 2004 to 20 October 2008. Courtesy of the HIGP Thermal Alerts System.

Date Time (UTC) Pixels Satellite
24 Aug 2004 1355 1 Terra
31 Aug 2004 1655 1 Aqua
30 Sep 2004 1710 1 Aqua
02 Oct 2004 1655 1 Aqua
04 Oct 2004 1350 1 Terra
09 Oct 2004 0440 1 Aqua
18 Oct 2004 1655 1 Aqua
20 Oct 2004 1350 1 Terra
25 Oct 2004 1705 1 Aqua
29 Oct 2004 1345 1 Terra
03 Nov 2004 1655 1 Aqua
10 Nov 2004 1700 1 Aqua
12 Dec 2004 1700 1 Aqua
21 Dec 2004 1400 1 Terra
21 Dec 2004 1655 1 Aqua
30 Dec 2004 1355 1 Terra
16 Feb 2005 1355 1 Terra
21 Feb 2005 1710 1 Aqua
15 May 2008 1355 1 Terra
20 May 2008 1710 1 Aqua
07 Jul 2008 1405 1 Terra
07 Jul 2008 1700 1 Aqua
06 Sep 2008 1345 1 Terra
11 Sep 2008 1700 1 Aqua
13 Sep 2008 1350 1 Terra
20 Sep 2008 1355 1 Terra
25 Sep 2008 1710 1 Aqua
04 Oct 2008 1705 1 Aqua
06 Oct 2008 1355 1 Terra
20 Oct 2008 1705 1 Aqua

Geologic Background. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. A smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. Only a few eruptions have been recorded in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998.

Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM), Saut Simatupang, 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/).